Terminating of electrical conductors

ABSTRACT

Terminating of an electrical conductor comprising a nonconductive core having conductive means on its surface and enclosed within an insulating jacket is effected by stripping the insulating jacket from at least one end of the conductor and casting an electrically conductive anchor member on the exposed end of the conductor, the anchor member being formed from a molten metal which shrinks upon solidification to provide an exceptionally secure mechanical and electrical bond between the core and the anchor member. The exposed end of the conductor may be kinked prior to the casting of the member.

United States Patent 1191 Hartz [111 1 3,813,643 [4 1 -May 28, 1974 1 1 TERMINATING OF ELECTRICAL CONDUCTORS [75] lnventor: Marvin E. Hartz, Bradford Woods,

[73] Assignee: Essex International, incorporated,

Fort Wayne, Ind.

[22] Filed: May 14, 1973 [21] Appl. No.: 360,090

Related U.S. Application Data [63] Continuation-in-part of Ser. No. 193,284, Oct. 28,

1971, abandoned.

[52] U.S. Cl. 339/223 S, 29/621, 29/630 A, 164/100, 164/111, 174/74 R, 338/66, 338/214, 338/332, 339/275 T, 339/276 T [51] Int. C1...H0lr 11/04, l-l0lr 11/22, l-l0lr 43/00 [58] Field of Search. 174/35 C, 74R, 75 R, 131 A; 29/619,621, 628, 630 R, 630 A, 164/98,

332; 339/223 R, 223 S, 256 C, 275 R, 275 T,

4 CONDUCTIVE WIRE 1,844,757 Greenwood ..339/275rx 2/1932 1,922,601 8/1933 Nolan 339/223 S 2,111,107 3/1939 Walde 339/275 T UX 2,175,251 10/1939 Carson .1 29/630 A 2,264,285 12/1941 Bennett 338/214 X 2,386,753 10/1945 Shield 174/131 A UX 3,243,763 3/1966 Elliott 339/223 S FOREIGN PATENTS-OR APPLICATIONS 701,838 1/1931 France 339/223 R 23,881 12/1914 Great Britain 338/332 610,109 10/1948 Great Britain 339/223 R Primary ExaminerLaramie E. Askin Attorney, Agent, or FirmLearman & McCulloch [57] ABSTRACT Terminating of an electrical conductor comprising a non-conductive core having conductive means on its surface and enclosed within an insulating. jacket is effected by stripping the insulating jacket from at least one end of the conductor and casting an electrically conductive anchor member on the exposed end of the conductor, the anchor member being formed from a molten metal which shrinks upon solidification to provide an exceptionally secure mechanical and electrical bond between the core and the anchor member. The exposed end of the conductor may be kinked prior to the casting of the member.

27 Claims, 8 Drawing Figures PATENTEHMAY 28 1914 CAST METAL NON METALLIC CORE 4 CONDUCTIVE WIRE FIG! NON METALLIC CORE CONTAINING CONDUCTIVE PARTICLES '1 TERMINATING or ELECTRICAL cououcroas RELATED APPLICATION This application is a continuation-impart of application Ser. No. 193,284, filed Oct. 28, 1971, now abandoned.

The invention disclosed herein relates to the tenninating of an electrical conductor and more particularly to the terminating of a conductor having radio frequency suppression characteristics. Conductors of the kind with which the invention is concerned are particularly well adapted for use in the manufacture of automotive ignition wires or cables.

An ignition cable manufactured for use in an automotive vehicle conventionally comprises a conductor capable of suppressing radiations disruptive to radio, television, and other electronic transmissions. Among suppressive conductors currently in use are resistive and inductive types, but in either event the conductor is sheathed in an insulating jacket and one end of the conductor conventionally is equipped with a terminal adapted for removable fitting on a spark plug. When the terminal is removed from a spark plug, such removal almost invariably is accomplished by the exertion of a pulling force on the conductor as a result of which considerable stress is exerted on the connections between the terminal, the insulating jacket, and the conductor. As a consequence, automotive manufactures have specified that the conductor/terminal assembly must be capable of complying with minimum standards as to mechanicaland electrical integrity when the assembly is subjected to what is known as a pull-off test in which the terminal is anchored and tension is applied to the conductor. f

A typical pull-off test specification requires that a cable and its terminal must be heat soaked for a period of 1 hour at a temperature of 200 F. and, while being maintained at that temperature, withstand a pound pull, applied at the rate of 2 pounds per second, for l minute without loss of electrical continuity. Such specification also requires that the cable and its terminal must not suffer loss of electrical continuity below twenty pounds pull, applied at the same rate, immediately following the 1 minute test referred to and while maintained at the specified temperature. Loss of electrical continuity is defined as the point at which the resistance of the cable and its terminal exceeds the maximum allowable resistance value fo the length of the lead under test.

Recent developments in automotive engine design to reduce objectionable emissionshave resulted in higher engine operating temperatures and consequent exposure of the ignition cables to such higher temperatures. The higher temperature has aggravated the retention problem of terminals on ignition cables of conventional construction. In an attempt to combat the adverse effects of the higher temperature environment, it has been proposed to extend the length of the terminal that couples the cable to the spark plug, thereby increasing the spacing between the spark plug and the cable end. Even so, the terminal is a conductor of heat and thus conducts some of the heat to the cable end. Furthermore, the increased length of the terminal and a corresponding increase in the length of any boot with which the terminal may be provided adds substantially to the cost of the cable and terminal assembly.

The desirability of providing a termination capable of withstanding the stresses to which it may be subjected has been recognized heretofore, of course, and many proposals for accomplishing such objective have been made. All of the commercially practiced proposals have relied, in part at least, upon the provision of a conductive cable having a non-metallic core formed of a material which has high tensile strength, the core being either impregnated with a conductive material or being wrapped with a conductive wire. The cable Conventionally is enclosed within an outer insulating jacket of rubber or rubber-like material resistant to heat, oil, and

"other deteriorating influences. The terminal must have an electrical connection withthe cables and should be bonded tightly to the insulating jacket so as to prevent the entry of foreign matter between the insulation and the terminal. The bond between the terminal and the insulating jacket has been troublesome, however, inasmuch as the rubber or rubber-like jacket material has less tensile strength than that of the cable core and, consequently, it is considerably more susceptible to failure as a result of being stressed in tension. This problem has been overcome to some extent by the provision of an inner sheath of insulationwithin which the cable is accommodated and by interposing a braided jacket formed of glass or textile fibers between the inner sheath and the outer insulating jacket. The braid reinforces the outer insulating jacket.

A cable of the kind having a reinforcing braid for the insulating jacket has a greater diameter than that of the cable itself, thereby creating a problem in the establishment of electrical conductivity between the cable and the terminal. This problem has been overcome by stripping the insulating and braided jackets from a sufficient length of the cable to enable the latter to be reversely turned or doubled back to extend alongside the adjacent end of the insulating jacket. The terminal then is fittedover the reversely turned cable and the end of the insulating jacket is crimped so as to grip tightly both the cable and the jacket. This construction, however, has several disadvantages. For example, as much as 1 inch, or more, of the cable must be doubled back alongside the insulating jacket to assure retentionof the cable within the terminal. The cable, therefore, initially must have an overall length greater than the length of the finished conductor, thereby representing an effective loss of a portion of the length of the cable. In many instances the cable is doubled back at both ends of the conductor. In the manufacture of ignition wires or cables over a period of time, therefore, the effective loss of length of the cable can be many hundreds of thousands of feet.

Another disadvantage of the doubled-back type cable and terminal assembly is that there appears to be no way to prevent oxidation from forming adjacent the juncture of the double-backed cable with the terminal. The oxidation frequently becomes corrosive resulting in arcing between the cable and the terminal. Such areing may result in destruction of the cable, the terminal, or both, with consequent failure of the conductor.

A considerable number of the aforementioned difficulties are overcome in a conductor constructed in accordance with the disclosure in US. Pat. No. 3,243,763 wherein'a conductive cable having a non-metallic core has a plastic bead formed on the exposed end of the core and a metallic, electrically conductive member crimped on the core between the bead and the adjacent end of the insulation. The bead, the conductive member, and the adjacent end of the insulation may be enclosed within a terminal which is crimped onto the insulation and the conductive member. Even in this construction, however, the effective length of the cable is reduced by the amount occupied by the bead. Moreover, so much time is required for the plastic bead to solidify and become rigidly fixed to the core that highspeed, automatic production of such conductors is deterred. In addition the environmental temperatures in many cases are so high that the plastic bead becomes soft, or even melts, thereby rendering the bead useless as a means for retaining the terminal on the cable.

Although an ignition cable constructed according to the invention does not require the use of a reinforcing braid or the like to enable it to withstand the pull-off test referred to earlier, such a braid may be interposed between the conductor and its insulating jacket or applied externally to the jacket, or both, if desired.

An object of this invention is to provide a radio frequency suppressive ignition cable construction which overcomes the disadvantages referred to above.

Another object of the invention is to provide a cable of the character referred to and which eliminates or greatly minimizes the cable and other material losses encountered in previously known constructions and which dispenses with the need for an inner insulation sheath and reinforcing braid.

Another object of the invention is to provide such a cable and terminal assembly which is virtually impervious to internal corrosion. I

A further object of the invention is to provide a method of producing a cable of the kind described and which is compatible with high-speed, automatic production equipment.

Other objects and advantages of the invention will be pointed out specifically or will becomeapparent from the following description when it is considered in conjunction with the appended claims and the accompanying drawings, in which:

FIG. 1 is a fragmentary, longitudinal sectional view of an ignition cable constructed in accordance with one embodiment of the invention;

FIG. 2 is a view similar to FIG. 1 and illustrating a typical terminal secured to one end of the cable;

FIG. 3 is a view similar to FIG. 1, but illustrating a modified form of cable;

FIG. 4 is a view similar to FIG. 3, but illustrative of another embodiment of the invention;

FIG. 5 is a view similar to FIG. 1, but illustrating a further embodiment of the invention;

FIG. 6 is a sectional view illustrating apparatus and a step in the manufacture of a cable according to a further embodiment of the invention;

FIG. 7 is a view similar to FIG. I, but illustrating the cable of FIG. 6; and

FIG. 8 is a view similar to FIG. 7, but illustrating another embodiment.

An ignition cable constructed in accordance with all embodiments of the invention comprises a non-metallic core I'composed of frangible material having an exceedingly high degree of tensile strength. The core may be formed of a suitable material such as a solid glass fiber strand, a plurality of glass fiber rovings, or a glass fiber rope, or any other material having the requisite tensile strength and the heat-resistant property hereinafter described. The core should be capable of suppressing radio frequency and, and if it is to be of the inductive impedence type, the core may be wound spirally about its surface with a metallic, conductive wire 2, as shown in FIGS. 1, 2, 5, 6, and 7, or, if the core is to be of the resistance type, the surface and interior of the core may be impregnated with conductive particles 2a, as is indicated in FIGS. 3, 4, and 8. The invention thus is applicable to the manufacture of either the resistive or the inductive type ignition cable.

The cable is encased within a single, extruded insulating jacket 3 of elastomeric material which may be either a conventional plastic or heatand oil-resistant rubber or rubber-like substance.

The insulated conductive cable is manufactured in long lengths which subsequently are cut into shorter lengths by conventional wire-cutting machinery. Following the cutting operation, or simultaneously therewith, depending upon the kind of machinery used, either or both ends of the cut length are stripped of insulation so as to expose a short length of the cable. The length of the exposed core need be no greater than 0.100 0.200 inch, but it can be as great as desired.

On and encircling an exposed end of the cable is cast a ductile, metallic, electrically conductive anchor member 4. The member 4 has a length corresponding substantially to the exposed length of the cable and may be die cast in situ onto the cable by means of any one of a number of different die casting machines, but it is preferred that the anchor member be formed on the exposed end of the cable as part of the conductor cutting and insulation stripping operation. This objective may be achieved by the use ofa Model 41 die casting machine manufactured by Fisher Gauge Limited, of Peterborough, Ontario, Canada.

The metal of which the anchor member 4 is made should be one having a sufficiently low temperature when molten to prevent damaging the core I, the conductive material carried by the core, and the insulation 3. Conversely, the core, the conductive material carried thereby, and the insulation should be capable of withstanding the temperature of the molten metal. Moreover, the metal from which the anchor 4 is made should be one which has a high shrinkage as it solidifies so as to establish an extremely tight, circumferential mechanical bond between itself and the core 1. The tight bonding between the anchor member and the core not only provides a bond of sufficient structural integrity between the core and the anchor member to prevent inadvertent separation thereof, within limits, but also establishes an excellent electrical connection between the anchor and the conductive material carried by the core. An alloy composed of 96 percent lead and 4 percent antimony having a liquidus temperature of 570 F. possesses all of these characteristics. Alloys of lead and other metals, such as tin, Zinc, and the like, atso may be used.

Of particular importance is the shrinkage during solidification of the metal constituting the anchor member 4. The rate of shrinkage is controlled by regulation of the temperature of the metal so that the metal gradually exerts a substantially uniform, radially compressive force along the whole of the cable end, thereby avoiding the sudden imposition of extremely high pressures at spaced intervals as occurs in conventional crimping operations. As a result, the solidified anchor member has a rigid mechanical bond with the cable end and provides total circumferential envelopment of the core material, but the substantially uniform application and distribution of the compressive force along the length of the cable-end avoids crushing or breaking of the core I.

Following the casting and solidifying of the anchor member 4, a tubular spark plug terminal 5 of conventional construction may be fitted over the anchor member and the adjacent end of the insulating jacket 3. The terminal then may be crimped circumferentially and radially inwardly as at 6 against the member 4 so as to anchor the terminal securely to the member 4. The ductility of the anchor member permits an extremely secure mechanical and electrical engagement to be effected between the anchor member and the terminal. Crimping of the terminal radially inwardly against the anchor member causes the latter to engage the core I even more tightly. It will be understood that the anchor member may be crimped inwardly regardless of the presence of the terminal 5.

It is preferred that the terminal also be crimped circumferentially and radially inwardly as at 7 adjacent the free end of the insulating jacket 3 and in such manner as to cause the end of the jacket to abut snugly the inner surface of the terminal and the confronting surface of the anchor member 4. The crimping of theterminal to the jacket 3 is not for the purpose of anchoring the terminal to the cable. The principal purpose is to provide an airand moisture-tight seal between the terminal and the insulating jacket and the anchor member 4.

The structural integrity of the connection between the anchor member 4 and the exposed end .of the conductive cable may be increased, if desired, by flaring or splaying the free end of the core as at 8 as shown in FIG. 3. If desired, the free end of the core may have a conical recess 9 formed therein. The anchor member 4 then is cast on the free end of the cable in the manner previously described.

If the recess 9 is provided at the free end of the core, the molten metal will occupy the recess as well as encircling the cable so that, as the metal shrinks during its solidification, it formsa tight bond. against the inner and outer walls of the recess, as well as against the adjacent portionof the cable.

According to the embodiment of the invention shown in FIG. 4, the free end of the cable 1 may be kinked or looped as at 10 to assume a predetermined configuration prior to being fitted with the anchor member 4. In this embodiment the length of the stripped end of the cable is greater than that of the earlier described embodiments but the entire length of cable encircled by the anchor member is gripped very tightly, thereby increasing the structural integrity of the joint between the cable and the anchor. Moreover, the kinked cable and the anchor interlock with one another.

Although the particular terminal 5 disclosed herein is one adapted for cooperation with a spark plug, it should be understood that other and different kinds of terminals may be used. Alternatively, it is possible in some instances for the cast anchor member itself to constitute a terminal. Such a construction is shown in FIG. 5 wherein a die-cast anchor member II has a somewhat bulbous shape the diameter of which is substantially greater than that-of the jacket 3. The shape of the member 11 is such as to enable it to fit into and be frictionally retained in the socket of a conventional automotive distributor. The member 11, or the member 4, may assume any one of a variety of shapes merely by changing the die-casting mold in which the member is formed.

FIG. 6 discloses a mold cavity 12 of a die casting machine such as has been referred to hereinbefore and into which the insulation-stripped end of a cable in introduced through an opening 13. The Iength of the stripped cable end is greater than the length of the cavity, but the whole of the stripped end nevertheless is introduced to the cavity. As a consequence, the stripped end of the cable is subjected to an axially compressive force and is crumpled or kinked in a random manner as is indicated at 14. Since the crumpling of the cable end is random, rather than according to a predetermined design, it will be understood that the configuration of the end as shown at 14 is representative or typical only, and that the end of the cable may assume any one of a large number of different configurations. In all, however, the stripped end of the cable spans the cavity and has a length greater than that of the cavity.

The difference in length between the stripped end of the cable and the cavity may vary, depending upon such factors as the cable/anchor retention strength desired and the diameter of the cavity. Excellent results have been obtained in constructions wherein the length of the stripped end of the cable is about twice the length of the cavity.

Following fitting of the cable end into the cavity 12, molten metal may be introduced to the cavity via a sprue 15 so as to form, following solidification, an anchor member 16 as shown in FIG. 7 having the characteristics referred to earlier. The member 16 could be shaped to form a terminal such as the terminal 11, or it may be fitted with the terminal 5.

The embodiment shown in FIG. 8 corresponds to that shown in FIG. 7 with the exception that the cable of the FIG. 8 embodiment comprises the non-conductive core I impregnated with conductive particles 2a.

In a conductor formed according to any of the embodiments of the invention the terminal 5 is anchored directly to the anchor member 4, rather to the insulating jacket 3, and the cable also is anchored directly to the member 4. As a consequence, tensile stresses imposed on the terminal are transmitted to the core of the cable, rather than to the insulation, thereby avoiding the necessity of providing a separate braided jacket or the like for reinforcing the insulation.

The materials from which the several parts of the construction are made may be so selected as to be relatively unaffected by the temperatures of the environment in which they operate, thereby avoiding terminal retention problems experienced with previously known constructions at elevated environmental temperatures.

Cable and terminal assemblies constructed according to all of the disclosed embodiments have been subjected to the pull-off test referred to hereinbefore and in all cases the assemblies exceeded the retention specifications. In 'the testing of the hooked and randomly kinked embodiments, the assemblies exhibited remarkable retention characteristics. For example, the testing of ten assemblies made according to FIG. 4 resulted in pull-off at an average tensile force of 31.67 pounds with a standard deviation of 3,73 pounds and a range of 26.1 to 36.8 pounds. Testing of randomly kinked samples according to FIG. 7 resulted in pull-off at an average tensile force of 31.72 pounds with a standard deviation of 2,74 pounds and a range of 27.2 to 35.9 pounds.

The disclosed embodiment of the invention are representative of presently preferred forms of the invention, but are intended to be illustrative rather than definitive thereof. The invention is defined in the claims.

I claim:

1. A termination construction for an electrical conductor composed of a non-conductive core having conductive means thereon, at least one end of said conductor projectingbeyond an insulating jacket surrounding the remainder of said conductor, said construction comprising a metallic, electrically conductive anchor member encircling only the projecting end of said conductor, said anchor member being cast in situ on said projecting end of said conductor and being'formed of a molten metal having a solidification shrinkage such as to cause said anchor member to grip circumferentially said core and the conductive means tightly over the length of said anchor member.

2. The construction according to claim 1 wherein said anchor member grips said core with sufficient force to prevent separation of said anchor member and said core when said anchor member and said core are subjected to a tensile force of at least 20 pounds applied at a rate not exceeding 2 pounds per second in an environmental temperature of at least 200 F.

3. The construction according to claim 1 wherein that portion of said core encircled by said anchor member is kinked. 1

4. The construction according to claim 3 wherein the kinked portion of said core is hook shaped 5. The construction according to claim 3 wherein the kinked portion of said core has a random configuration.

6. The construction set forth in claim 1 wherein said one end of said core is splayed.

7. The construction set forth in claim 1 wherein said one end of said core. has a recess therein, said recess containing metal constituting part of said anchor member.

8. The construction set forth in claim 1 wherein said anchor member is crimped inwardly toward said core.

9. The construction set forth in claim 1 wherein said anchor member is crimped circumferentially and radially inwardly thereof.

10. The construction set forth in claim 1 including an electrically conductive terminal having a tubular portion in which said anchor member is accommodated.

11. The construction set forth in claim wherein one end of said tubular portion also accommodates a portion of said jacket adjacent said one end thereof.

12. The construction set forth in claim 11 wherein said one end of said tubularportion is crimped inwardly toward said jacket.

13. The construction according to claim 1 wherein said anchor member wholly encloses the projecting end of said core.

14'. The construction according to claim 1 wherein said core is composed of a frangible material relatively strong in tension but relatively weak in compression.

15. The construction according to claim 14 wherein said material is glass.

16. The construction according to claim 1 wherein said exposed end of said core and said anchor member are substantially coextensive in length.

17. The construction according to claim 1 wherein the length of said exposed end of said core encircled by said anchor member is greater than the length of said anchor member.

18. A method of terminating an electrical conductor enclosed within an insulating jacket, said method comprising stripping said jacket from at least one end of said conductor to expose a predetermined length of said conductor at one end thereof; applying an axially compressive force to the exposed end of said conductor for kinking the exposed end of said conductor; casting in encircling relation about the exposed end of said conductor an electrically conductive anchor member formed of molten metal which shrinks upon solidification, vvhereby upon solidification said anchor member tightly grips the encircled conductor; and solidifying said molten metal.

19. The method according to claim 18 including casting said anchor member about the whole of the exposed end of said conductor.

20. The method according to claim 18 including kinking said exposed end of said conductor to assume a randum configuration.

21. A method of terminating an electrical conductor composed of a nonconductive, frangible core having conductive means thereon and positioned within an insulating jacket, said method comprising stripping the jacket from at least one end of said conductor to expose one end of said core and the conductive means thereon; casting in situ on said end of said conductor an anchor member encircling said one end of said conductor and formed of electrically conductive, molten metal which shrinks upon solidification; and solidifying said molten metal at a rate such as to cause said anchor member to shrink gradually and exert on said core a substantially uniform, radially compressive force sufficient to form a mechanical bond with said core without crushing of the latter.

22. The method according to claim 21 including flaring said one end of said core prior to casting said anchor member thereon.

23. The method according to claim 21 including kinking said one end of said core prior to casting said anchor member thereon.

24. The method according to claim 21 including kinking said one end of said core to a hook-shaped configuration prior to casting said anchor member thereon.

toward said jacket.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3, 813,643 Dated May 28 1974 Inventor(s) Marvin E. Hartz It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

Column 4, line 1, after "frequency" insert radiations Signed 'and sealed this 1st day of October 1974.

(SEAL) Attest: v

McCOY M. GIBSON JR. C. MARSHALL DANN Attesting Officer Commissioner of Patents FORM P0-1050 (10-69) USCOMM-DC c0 U.ST GOVERNMENT PRINTING OFFICE: 19 89 0-366-834,

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3, 813,643 Dated Mal 2L 1974 Inventor(s) Marvin E. Hartz It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

Column 4, line 1, after "frequency" insert radiations Signed and sealed this 1st day of October 1974.

(SEAL) Attest:

MCCOY M. GIBSON JR. C. MARSHALL DANN Attesting Officer Commissioner of Patents )RM powso H0439) USCOMM-DC 60376-P69 U.Si GOVERNMENT PRINTING OFFICE: I969 417-366-384. 

1. A termination construction for an electrical conductor composed of a non-conductive core having conductive means thereon, at least one end of said conductor projecting beyond an insulating jacket surrounding the remainder of said conductor, said construction comprising a metallic, electrically conductive anchor member encircling only the projecting end of said conductor, said anchor member being cast in situ on said projecting end of said conductor and being formed of a molten metal having a solidification shrinkage such as to cause said anchor member to grip circumferentially said core and the conductive means tightly over the length of said anchor member.
 2. The construction according to claim 1 wherein said anchor member grips said core with sufficient force to prevent separation of said anchor member and said core when said anchor member and said core are subjected to a tensile force of at least 20 pounds applied at a rate not exceeding 2 pounds per second in an environmental temperature of at least 200* F.
 3. The construction according to claim 1 wherein that portion of said core encirCled by said anchor member is kinked.
 4. The construction according to claim 3 wherein the kinked portion of said core is hook shaped.
 5. The construction according to claim 3 wherein the kinked portion of said core has a random configuration.
 6. The construction set forth in claim 1 wherein said one end of said core is splayed.
 7. The construction set forth in claim 1 wherein said one end of said core has a recess therein, said recess containing metal constituting part of said anchor member.
 8. The construction set forth in claim 1 wherein said anchor member is crimped inwardly toward said core.
 9. The construction set forth in claim 1 wherein said anchor member is crimped circumferentially and radially inwardly thereof.
 10. The construction set forth in claim 1 including an electrically conductive terminal having a tubular portion in which said anchor member is accommodated.
 11. The construction set forth in claim 10 wherein one end of said tubular portion also accommodates a portion of said jacket adjacent said one end thereof.
 12. The construction set forth in claim 11 wherein said one end of said tubular portion is crimped inwardly toward said jacket.
 13. The construction according to claim 1 wherein said anchor member wholly encloses the projecting end of said core.
 14. The construction according to claim 1 wherein said core is composed of a frangible material relatively strong in tension but relatively weak in compression.
 15. The construction according to claim 14 wherein said material is glass.
 16. The construction according to claim 1 wherein said exposed end of said core and said anchor member are substantially coextensive in length.
 17. The construction according to claim 1 wherein the length of said exposed end of said core encircled by said anchor member is greater than the length of said anchor member.
 18. A method of terminating an electrical conductor enclosed within an insulating jacket, said method comprising stripping said jacket from at least one end of said conductor to expose a predetermined length of said conductor at one end thereof; applying an axially compressive force to the exposed end of said conductor for kinking the exposed end of said conductor; casting in encircling relation about the exposed end of said conductor an electrically conductive anchor member formed of molten metal which shrinks upon solidification, whereby upon solidification said anchor member tightly grips the encircled conductor; and solidifying said molten metal.
 19. The method according to claim 18 including casting said anchor member about the whole of the exposed end of said conductor.
 20. The method according to claim 18 including kinking said exposed end of said conductor to assume a randum configuration.
 21. A method of terminating an electrical conductor composed of a nonconductive, frangible core having conductive means thereon and positioned within an insulating jacket, said method comprising stripping the jacket from at least one end of said conductor to expose one end of said core and the conductive means thereon; casting in situ on said end of said conductor an anchor member encircling said one end of said conductor and formed of electrically conductive, molten metal which shrinks upon solidification; and solidifying said molten metal at a rate such as to cause said anchor member to shrink gradually and exert on said core a substantially uniform, radially compressive force sufficient to form a mechanical bond with said core without crushing of the latter.
 22. The method according to claim 21 including flaring said one end of said core prior to casting said anchor member thereon.
 23. The method according to claim 21 including kinking said one end of said core prior to casting said anchor member thereon.
 24. The method according to claim 21 including kinking said one end of said core to a hook-shaped configuration prior to casting said anchor member thereon.
 25. The method according to Claim 21 including kinking one end of said core to a random configuration prior to casting said anchor member thereon.
 26. The method according to claim 21 including fitting a tubular, electrically conductive terminal onto said anchor member and crimping said terminal against said anchor member.
 27. The method according to claim 26 including fitting said tubular terminal also over said jacket adjacent said one end of said core and crimping said terminal toward said jacket. 